Merritt Patterson joins 'Ravenswood's' cast

She will play Tess, Olivia’s (played by Elizabeth Whitson) former best friend, who isn’t involved with the curse. Tess will appear in the subsequent episodes following “Ravenswood’s” Halloween episodes.

Patterson, represented by Play Management and Mosaic, appeared in “Life Unexpected,” the CW’s first “The Selection” pilot and “Percy Jackson & the Olympians” The Lightning Thief.”

Tyler Blackburn will leave “Pretty Little Liars” and star in “Ravenswood” as a regular. He plays Caleb, Hanna’s (played by Ashley Benson) boyfriend. He’ll travel to Ravenswood during the Halloween installment of “Pretty Little Liars” joined by Abel (Brett Dier, “L.A. Complex”) and his character’s twin Olivia (Whitson is a relative newcomer, so let’s all make her feel welcome).

“Pretty Little Liars” characters Toby (played by Keegan Allen) and Spencer (played by Troian Bellisario) will also be headed to Ravenswood in an upcoming episode.

“Ravenswood” still needs to fill the part of Miranda (who will be in the Halloween episodes) and another character who literally will be named later.